In a mobile communication system, the mobility management of a User Equipment (UE) is a fundamental and necessary logical function of the mobile communication network.
For the purpose of addressing and identifying the UE in the mobility management, a Core Network (CN) divides a network into a series of areas in terms of logical architecture, and allocates a separate identity for each of the areas. Depending on the division criteria, the network is divided into different areas, including, for example, a Tracking Area (TA) and a Routing Area (RA) provided with a Tracking Area Identity (TA ID) and a Routing Area Identity (RA ID) respectively.
For the sake of simplification, the reference to an area below is made by taking the Tracking Area as an example.
The Core Network allocates a specific area (which is indicated by at least one TA ID) for a DE attached to the network, and when the DE moves from the current allocated area to an unallocated area, the UE initiates the TA Update procedure to the network.
A Mobility Management Entity (MME) in the Core Network is responsible for the mobility management of the UE, and the MME includes, but not limited to a Mobile Switching Center (MSC), a Serving GPRS Support Node (SGSN), and a signaling terminating node at a non-access layer of a core network of the Evolved Packet System (EPS) of the Third Generation Partnership Project (3GPP).
The Core Network includes a plurality of MMEs, each of which manages a certain range of areas, that is, each MME manages a limited range of areas. It is possible for a UE to move out of an area allocated by the current MME to the UE, and further move out of the entire areas managed by the current MME.
In the traditional 3G mobile communication system, since the MME allocates to the UE a single TA ID, i.e. one TA, the UE may traverse multiple TAs within a short period of time when moving at a high speed, as a result, multiple TA update procedures are caused, signaling exchanged between the network and the UE is increased greatly, and network resources are wasted.
In view of the above, an MME allocates a TA List containing multiple TA IDs to a UE in the 3GPP EPS system. Since the TA List includes multiple TA IDs, the range of areas allocated for the UE is increased, so that the TA updates during the movement of the UE are reduced and the utilization of the network resources are improved.
To allocate a TA List for the UE, it is necessary for the MME to determine as possible the area that the UE is moving to so that an appropriate TA List is allocated to the UE in order to reduce as possible the location updates caused during the fast movement of the UE.
At present, however, the MME allocates a new TA List for the UE based on a single TA ID in the original TA List that is sent by the UE, which is insufficient for the MME to allocate a new appropriate TA List for the UE. Therefore, the areas allocated by the MME for the UE are possibly inappropriate and multiple location updates are caused during the fast movement of the UE, thus, a large amount of signaling is still exchanged between the network and the UE, and the network processing resources are still wasted.